Steam-engine



(No Model.)

E. W. CURTISS. STEAM ENGINE.

Patented Mar. 31, 1891.

Parati rrrcn.

EITWRD CURTISS, OF PORTLAND, OREGON.`

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 449,208, dated March 31, 1891. A Application filed December 11, 1890. Serial No. 374,288. (No model.)

T0 @ZZ whom t may concern:

Be it known that I, EDWARD IV. CURTISS, acitizen of Portland, in the county of Multnomah and State of Oregon, have invented certain new and useful Improvements in Steam-Engines; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an improvementin steam-engines, and more particularly to an improved valve mechanism for engines employing more than one cylinder and piston, one of the objects of the invention being to produce a valve mechanism which shall be of simple construction and effectual in operation.

A further object is to provide a steam-engine having more than one cylinder' and piston, with valves so arranged that each shall alternately act-nate the other.

Vith these objects in View the invention consists in certain novel features of construction and combinations and arrangements of parts, as hereinafter set forth, and pointed out in the claims. 1

In the accompanying drawings, Figure l is an elevation of my improved engine. Fig. 2 is a view on the line as x of Fig. l. Fig. 3 is a sectional view of the valve mechanism. Fig. 4 is a diagonal-view showing two cylinders, valves, and steam and exhaust pipes and ports.

A represents any suitable frame-work for supporting the main cylinders B B', each of which is provided with a piston C and a piston-rod C', the latter being ot' comparatively large diameter, as shown in Fig. 2, so that the amount ot area on the under side or face of the pistons will be considerably less than the area of the upper face of the pistons exposed to the action of steam.

Located in close proximity to each cylinder B B is a valve chamber or cylinder D D', havin g heads D2 D2, with the centers of which chambers steam-ducts a a communicate, said ducts being adapted to connect the valvechests with the ends of the main cylinders B B as shown in Fig. 4. The main cylinders B B are also provided with ducts li, which pass through their walls at points in close a steam-inlet pipe j' communicates, and the annular recesses d are connected by a pipe f', with which an exhaust-pipe g communi- Cates.

Each valve-chest is provided with a'piston` Valve of the form substantially as shown in Figs. 3 and L.t--that is to say, each lpistonvalve is provided with two grooves h 7L', adapted to control the ingress of steam to and the egress of steam from the cylinders.` The piston-valves are provided with stems t', to which connected by a rock-shaft or walking-beam F, which latter is pivotally connected at its center to the fram e-work A. It is evident that the parts maybe reversed from the positions above described and the piston-rods made to project up instead of down, or the engine may be arranged horizontally.

The engine being constructed as above set forth, live steam is admitted to the under side of the piston in one of the cylinders and causes said piston to rise. As it reaches the upper end of the cylinder, (in a vertical engine,) the piston passes over the port or duct Z7, which leads from the cylinder into the upper end of the valve-chest. The steam under the piston is now free toV pass to the valvechest, and the steam-pressure throws this valve down to a position which exhausts the steam from beneath the piston to the upper side; but in throwing this valve down the valve attached to the other end of the rockshaft is thrown up and live steam admitted under the other piston, which causes it to rise while the first piston is falling. After the valves are thrown the steam which throws them exhausts back through the duct b. The pressure on the end of the valve after it has been thrown (or just before it is moved up by the rock-shaft) is the same as the exhaust and is very small, owing to the effect of ex- -links t" are connected, and the links t" are IOO pansion, and the pressure on the other valve at this same instant-fis boiler-pressure. Hence the valves move instantly and give a sharp cutoff, which is of great importance. In a variable-stroke engine, by properly proportioning lthe smaller area of the piston, the downstroke, with the help ot' gravity, is made in a shorter time than the upstroke.v When the piston in its movement down is stopped from any canse, it remains at rest until the other piston (which is in the meantime moving up) passes the duct b, which admits steam abovev the valve, when both valves will again move, one up and other down.

The arrangement of parts and the construction ydisclosed are designed more particularly for stamp-mills; but I do not confine the employment of the novel features of the device to .stamp or other mills, but consider' myself at liberty to employ them in any kind of enfgine where 'they can be used to advantage. I have shown the walking-beam connecting the valves connecting the lower ends of the valves; but it is evident that the beam can be arranged on top and equally good results secured, l

Slight changes might he made in the details of construction of my invention without departing from the spirit thereof or limiting its scope. Hence I do not wish to limit myself to the precise details of construction herein described; but,

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In a steam-engine, the combination, with two cylinders, of a piston in each cylinder, a valve for each cylinder, a walking-beam or rock-shaft connecting said valves, and ports for admitting steam between the heads of the valve-chambers and the adjacent ends of the valves for actuating the latter in one direction, substantially as set forth.

2. In a steam-engine, the combination` with two Acylinders and pistons therein, of a valvechest for each cylinder, a piston-valve in each valve-chest, each piston-valve having two -annular grooves, a rock-shaft connecting said piston-valves, and steam-ports for admitting steam to thevalve-chests near one end of the latter for actuating the valves in one direction, substantially as set forth.

3. In a steam-engine, the combination, With two cylinders and pistons therein, cf a valvechest for each cylinder, two pipes connecting vsaid valve-chests, an inlet-pipe communicating with one of said connecting-pipes and an exhaust-pipe communicating with the other connecting-pipe, valves in said valve-chests, and a rock-shaft connecting said Valves, substantially as set forth.

4. In a steam-engine, the combination,with two cylinders and pistons, of a valve-chest for each cylinder, said cylinders being provided with ducts connecting the ends of the cylinders with the valve-chests, and each cylind'er being provided with a duct adapted to connect the cylinders and valve -chests in proximity to the upper ends of the latter, and piston-valves in said valve-chests, substantially as set forth.

5. In asteam-engine, the combination, with two cylinders and pistons therein, of valvechests lfor said cylinders, piston-valves in said valve-chests, a link connected to each valve, and a rock-shaft pivoted at its cen-ter and connected at its ends to said links,` substantially as set forth.

6. In asteam-engine, the combination, with two cylinders and pistons therein, of a valvechest for each cylinder, each valve-chest .being provided with annular recesses, pipes connecting said valvechests and commfnnieating with lsaid recesses, a piston-valve in each valve-chest, .a rock-shaft lconnecting said piston-valves, and steam-ports for admitting steam to the valve-chests near one end of the latter for actuating the valves in one direction, substantially as set forth. y

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

E. IV. CURTISS.,

Witnesses:

R; L. TAFT, S. E. TAFT. 

